Pump construction



' July 29, 1941-.- w uN s 2,251,231

PUMP CONSTRUCTION Filed Feb. 2, 1939 2 Sheets-Sheet l 2 W INVENTOR ATTORN EYS July 29, 1941. w, 1', U s 2,251,231

PUMP CONSTRUCTION Filed Feb. 2, 1939 2 Sheets-Sheet 2 INVENTOR ATTO FYS- thereof, this being the Patented July 29, 1941 UNITED STATES PATENT OFFICE PUMP CONSTRUCTION William T. Runals, Akron, Ohio, assignor to The Firestone Tire & Rubber Company, Ohio, a corporation of Ohio Akron,

Application February 2, 1939, Serial No. 254,189 Z CIaims. (Cl. 103104) I latex, which is a colloidal dispersion of rubber particles in a watery serum, from one place to another whenever such transfer cannot be done by gravity because even though rubber latex is liquid, it has low resistance to coagulation, or solidification. This tendency to solidify is increased when the latex is subjected to mechanical agitation, or velocity changes, such as occur in piunping it from one place to another. When ordinary pumps are used for pumping latex, the pump only runs a very short time before becoming clogged with solidified latex, or rubber produced by numerous dispersed particles being unified. This necessitates dismantling the pump, removing the rubber, and reassembling the pump before more latex can be pumped. Obviously this is undesirable and makes the transfer of latex a diificult and expensive task.

Applicant has found out why ordinary pumps have solidified latex and has constructed an inpensive pump which is specially designed for pumping latex without causing solidification general object of the invention.

Further objects of the invention are to providea pump in wlich the fluid within the pump can not contact the bearings of the pump; a pump that prevents any formation of eddy currents of the liquid in the pump; a pump in which both surfaces of the impeller are supplied with material to be pumped; which has no sharp corners or obstructions therein whereby sharp impact of the pumped material on the pump, is avoided.

While the invention will be described with reference to latex, it is thought that the present pump construction is adapted to pump other colloidal dispersions without producing coagulation.

The present invention will be.described with reference to the accompanying drawing in which:

Figure 1 is a vertical sectional elevation of one embodiment of the invention;

Figure 2 is a front elevation of the impeller means of the invention;

Figure 3 is a vertical cross section on line 3-3 of Figure 2; and l Figur 4 is a fragmentary elevation on line 4-.4 of Figure 3.

Referring more specifically to the centrifugal pump shown in the accompanying drawings, a housing or stator I is provided for the pump 'and it is fixedly mounted upon base means (not ,shown). The stator II] has an axial bore II and a face surface l2 that is smoothly curved, or

and pumping equipment dished, inwardly from a point adjacent its outer periphery. A rearwardly directed, integral flange I3 is formed on the stator ill at its periphery. This flange 13 has an' integral extension l4 formed thereon at the base thereof to facilitate mounting the pump. Figure l shows that the,

flange l3 increases in length from top to bottom of the pump to strengthen the pump housing. A cover plate l5, having a smoothly curved, or dished, face surface I6, is secured to the stator II) in any suitable manner, such as by capscrews IT, with theface surfaces being adjacent so that they form a chamber l8 therebetween. The capscrews ll engage with threaded holes formed in acircular flange 2| which is integral with the face plate and is positioned at the periphery thereof. The cover plate has an aperture I 9 formed therein at its axis to provide an inlet to th chamber l8 from which ,the latex is pumped as described hereinafter. Figure -1 indicates that an annular chamber or recess 22 is formed by the face surface l6 of the cover plate l5 and the stator at the periphery thereof into which the impeller does not extend. The recess 22 gradually and progressively increases in volume from the top of the pump around the periphery of the pump. The portion of the cover plate defining the recess is positioned increasingly farther away from the axis of the bore ll until it is completely severed from the cover plate and forms a pipe 23. Sometimes it may be desirable to increase the radius of the cover plate gradually in extending it around the pump to 'increase'the volume of the recess 22. The pipe 23 extends substantially tangentially from the cover plate and forms the outlet of the pump. This facilitates discharge of the pump.

To provide means for forcing latex from'the chamber la, a shaft 24 is journalled in the stator l0 and its end extends into the'chamber. The

shaft is rotated by any suitable means (not oil, or rounded, so that .no sharp corners are presented to contact the pumped material. The

axial feed of the latex permits the impeller arms to contact the latex initially with-a minimum of disturbance thereto because the arms are smoothly curved to urge the latex gradually outwardly of the chamber and the web 25 and shaft 24 has forced the latex in that direction upon tics are important in pumping latex. Of course;

the arms 21 are designed so that rotation of the shaft and impeller forces latex in the chamber towards the periphery of the pump and finally from the chamber through the outlet.

Latex is also supplied to the chamber from the face surface I! of the stator, Pipes 3|, which connect to a latex supply, engage with fittings 32 engaged with the stator Ill and holes 33 are formed through the stator to permit passage of the latex to the chamber. Thus latex from the input I9 is engaged by the arm bases 21a and forced outwardly of the chamber while latex from the pipes 3| is contacted by the arm bases 21b to be forced outwardly in a similar manner. Constructing the arms on both sides of the web so that they substantially fill the chamber acts to prevent formation'of eddies in the chamber I8.

A further feature of the invention: is that the present construction prevents latex in the chamber from seeping along the portion of the shaft 24 that is journalled in bushing 34, which preferably has soft metal 34a inlaid in the bore thereof. A clrcumferentially extending recess 35 is formed in the bushing and a hole 36 forms a conduit between the recess and the outer surface of the bushing. A liquid, preferably water, is forced into the recess 35 under pressure from a pipe 31 that engages with a fitting 38 in the stator I 0. A hole 39 connects the fitting 38 with the conduit 36 formed in the bushing.

. Thus the fluid in the recess 38, being under pressure, flows, or gradually seeps, out along the shaft 24 until it meets the impeller at which time it moves along the edge of the impeller until it is forced into the chamber. may move along the shaft between it and the impeller. In all events, the impeller, shaft, and bushing form tight contacts with each other whereby only a small volume of liquid can be forced from the recess 35 into the chamber l8 in a relatively long time. Obviously this liquid flow prevents counter flow of latex from the chamber so that the latex cannot seep into the minute journal space between a stationary and a moving part. This differs the invention from prior pumping systems in which latex would seep into the bearing means and be coagulated to impair the pumps operation. Suitable packing material may be placed in a second recess 40 formed in the bushing 34 to prevent excessive water flow into the chamber l8.

A packing gland 4| engages with the stator l and forces packing 42 against the bushing 34 and the portion of the shaft 24 coming therefrom to prevent leakage of water therefrom and to complete the pump.

Usually it is desirable to form the face surfaces I2 and Hi from a metal, such as chromium or nickel, which has no deleterious effect on rubber and which may be plated onto a metalbase member. The pump construction facilitates maintenance thereof as the members forming same can easily be dissembled and buffed or polished to keep their surfaces smooth'and clean, this being very desirable in this type of pump.

From the foregoing description it should be seen that certain elements of ordinary pumps which have been found objectionable in pumping latex have been eliminated and that several new constructional features are present in the pump to adapt it for pumping latex.

While a written description and illustration of one embodiment of the invention is disclosed herein, it will be understood that various modifications can be made without departing from the Some liquid scope of the invention as defined in the appended claims.

What is claimed is:

1. A centrifugal pump for latex, said pump comprising a stator member, a cover 'plate secured to said stator member, said stator member and cover plate having smoothly contoured opposed faces forming a chamber therebetween, the surfaces defining the chamber converging toward the periphery thereof, a shaft journalled in said stator member and extending into said. chamber, bearing means journalling said shaft in said stator, said bearing means having an angular circumferential recess therein, means connected to said recess to maintain a liquid under pressure in said recess to urge liquid axially along said shaft and-into said chamber to prevent any latex in said chamber from flowing back along said shaft, an impeller having a central web portion and curved blades extending radially therefrom and laterally from both sides thereof fixedly secured to the portion of said shaft in said chamber, the axially outer surfaces of said blades being smoothly contoured to mate with the faces of said cover plate and stator member, an inlet formed in said cover plate and adapted to feed latex into said chamber at the axis of said shaft, a second inlet formed in said stator member so that latex can be fed to both sides of said impeller simultaneously, the portion of said impeller blades adjacent said cover plate extending appreciably farther from said web than the portion thereof adjacent said stator, the ends of said blades adjacent said first inlet being beveled to present gradually increasing areas of said blades to latex fed into the pump, said blades being smoothly curved throughout their entire extent and backwardly relative to the direction of rotation to force latex in said chamber to fiow smoothly therefrom as said impeller is rotated, and a smoothly contoured outlet for the pump tangentially connected to the peripheral portion of said chamber.

2 A centrifugal pump for latex, said .pump comprising a stator member having a face surface which is smoothly curved inwardly from a point adjacent its outer edge, a cover plate having a face surface that is smoothly curved inwardly from a point adjacent its outer edge secured to said stator member, the face surfaces of said stator member and cover plate being opposed to form a chamber therebetween, the surfaces defining the chamber converging toward the periphery thereof, a shaft jourrialled in said stator member and extending into said chamber, an impeller having a central web portion and curved blades extending radially therefrom and laterally from both sides thereof associated with the portion of said shaft in said chamber, the radially outer surfaces of said blades being convex and being smoothly curved throughout their entire extent and backwardly relative to the direction of rotation, said blades being constructed and arranged to force any latex in said chamber continuously and smoothly therefrom upon rotation of said impeller, means associated with both said cover plate and said stator member adjacent the centers thereof for feeding latex to both sides of said impeller simultaneously, the ends of said blades adjacent said cover plate inlet being beveled off to present gradually increasing areas of said blades to latex fed into the pump, and a smoothly contoured outlet for the pump substantially tangentially connected to the peripheral portion of said chamber.

WILLIAM T. RUNALS. 

